I have a 4-year-old male and a 3-year-old female miniature schnauzer. Over the past year, the male has been extremely jealous of the female, often resulting in a dogfight. He also jumps on her if she even so much as looks at him while he’s eating. What is causing this?
From the Editors of The Dog Daily
The problem you describe is common among dogs of many breeds. Miniature schnauzers vary tremendously in personality. Some miniature schnauzers spoil easily (because they are so cute and lovable) but have dominant personalities, as you've learned the hard way. A dog's level of dominance is partially determined by genetics, and puppies will even tend to show such qualities very early on.
Your male dog is asserting his dominance in your pack, overpowering you and your female dog. You need to be the alpha force of your family. Has the male been neutered and the female spayed? Unneutered males tend to be more aggressive, but dominance problems can surface in neutered dogs too.
Your dog needs a round of basic training and socialization from a trained professional. If you've done this before, a refresher course is due. Most pet stores offer such services, and you might also consult with your dogs' veterinarian for a recommendation.